SETXOFFSET

Purpose:

Specifies the x-offset of a series.

Syntax:

SETXOFFSET(series, xoffset)

series

-

Optional. A series or table, defaults to the current Window.

xoffset

-

A real, the desired starting X value of the series.

Example:

setxoffset(W1, -10.0)

 

sets the offset of the series in W1 to -10.0.

Example:

To set the offset of W1 to the offset of W2:

 

setxoffset(W1, xoffset(W2))

Remarks:

Many series have X values that are monotonically rising by a constant X increment such that:

 

image\xy01.gif

 

A series with X values of this form is referred to as an interval series. Because any X value from an interval series can be computed with:

 

image\XY02.gif

 

an interval series requires only the DELTAX and XOFFSET values to determine the X values. Thus, for an interval series, explicit X values are not necessary, decreasing the data storage requirements by a factor of 2. Also, because the X values for an interval series are regularly monotonic, speed optimizations for plotting and computations are available.

 

See XY to create a series with irregularly spaced X values.

 

Functions such as AUTOCOR, CROSSCOR and AMPDIST display the correct X axis values.

 

EXTRACT also sets the offset. For example, to extract 128 points at index 100 and set a zero x offset, use:

 

extract(W1, 100, 128, 0.0);

 

The Import Utilities recognize the optional header keyword X_OFFSET, so you can specify the offset when importing data files.

See Also:

DELAY

SETDELTAX

SETDELTAY

SETX

SETYOFFSET

XOFFSET

XY

YOFFSET